Citations

8006 Background: In 2 randomized phase 3 trials of RRMM patients (pts), DRd (POLLUX) or DVd (CASTOR) significantly improved PFS and deepened responses compared with Rd or Vd alone, respectively. The novel mechanism of action of daratumumab (D) may improve the poor prognosis associated with high-risk cytogenetic abnormalities in RRMM. Therefore, we examined the efficacy of DRd and DVd among RRMM pts with standard (std) or high cytogenetic risk status. Methods: Bone marrow aspirates were collected at screening and assessed centrally via next generation sequencing (NGS). Pts with high-risk cytogenetics included those who had ≥1 of the following abnormalities: t(4;14), t(14;16), or del17p; std-risk pts were defined as those confirmed negative for these abnormalities. Efficacy analyses included PFS and ORR. Results: Samples from 311/569 pts in POLLUX and 353/498 pts in CASTOR were assessed via NGS. In POLLUX, the median duration of follow-up was 17.3 months. Significantly longer median PFS and numerically higher ORR were observed with DRd vs Rd among high-risk patients, and significant improvements in these outcomes were observed in std-risk patients (Table). In CASTOR, the median duration of follow-up was 13.0 months. Significantly longer median PFS and higher ORR were observed with DVd vs Vd among both high- and std-risk pts (Table). Concordance rates for t(4;14), t(14;16), and del17p were high (88%-98%) between NGS and FISH. Updated data, including subgroup analyses, will be presented. Conclusions: In RRMM pts, the addition of D to standard-of-care regimens improved outcomes regardless of cytogenetic risk status. Targeting CD38 by combining D with Rd or Vd appears to improve the poor outcomes associated with high-risk cytogenetic status. See table. Clinical trial information: NCT02136134 and NCT02076009. [Table: see text]

4519 Background: Tandem HDC with carbo/etoposide (CE) is curative for a portion of relapsed GCT pts. However, outcomes of refractory or high-risk relapsed pts remain poor. We tested a new HDC regimen of GemDMC, based on DNA damage repair inhibition. We combined BEV with HDC given their potential synergy and the high vascularity of GCT metastases. Methods: Eligibility: Intermediate (int)/high-risk (Beyer Model), creatinine ≤1.8 mg/dL and adequate organ function. HDC included BEV (5 mg/kg) preceding GemDMC (HDC #1) and ifosfamide/CE (ICE) (HDC #2). Following accrual of 42 pts, we amended the trial omitting BEV. The trial was powered to distinguish a target 50% 2-yr RFS from an expected 25% in this population. Results: We enrolled 69 male pts in cohorts 1 (BEV, N=42) and 2 (no BEV, N=27) (Table). Pts were heavily pretreated and most had refractory tumors. Main AE: mucositis and renal (4 HDC-related deaths in cohort 1, 1 in cohort 2). Tumor markers normalized in 90% pts with active tumors at HDC. After HDC, 19 pts were in CR and 28 in PRm- (of these, 22 had residual lesions resected with no viable tumor found in 20/22, 2 xRT, 4 monitored). Median f/u = 39 (2-105) mo. The 2-yr RFS rates in cohorts 1 and 2 = 52% and 78%, respectively. Their respective 2-yr OS rates = 55% and 81%. Conclusions: Sequential HDC with GemDMC–ICE shows encouraging outcomes in heavily pretreated and refractory GCT, exceeding the anticipated results. Addition of BEV increases toxicity but not tumor control. Clinical trial information: NCT00936936. [Table: see text]

TPS4148 Background: Cancer stem cells are considered to be fundamentally important for resistance to therapy, recurrence and metastasis. Napabucasin is a first-in-class cancer stemness inhibitor identified by its ability to inhibit STAT3-driven gene transcription and spherogenesis of cancer stem cells (Li et al, PNAS 112(6):1839, 2015). Preclinical studies suggest that napabucasin sensitizes heterogeneous cancer cells to chemotherapeutic agents, including nab-PTX and gem. Encouraging anticancer activity in mPDAC was observed in a phase Ib (El-Rayes et al, ASCO 2016) study of 37 pts, reporting 93% (28/30) disease control rate (DCR) and 50% (15/30) overall response rate (ORR), with 1 complete and 14 partial responses and prolonged disease control ( > 24 wks) in 57% (17/30) of pts who have had a RECIST evaluation. On the basis of these data, a phase III trial is being conducted in North America, Europe, Australia and Asia. Methods: This study (ClinicalTrials.gov NCT02993731) will assess the efficacy of napabucasin+nab-PTX+gem vs nab-PTX+gem in pts with mPDAC (n = 1132). Pts must have been diagnosed with mPDAC < 6 weeks prior to randomization and not have received treatment for metastatic disease. Pts are randomized in a 1:1 ratio to receive napabucasin 240 mg PO twice daily continuously plus nab-PTX+gem IV weekly for 3 out every 4 weeks, or nab-PTX+gem IV weekly for 3 out every 4 weeks. Pts will be stratified by geography, performance status and presence of liver metastases. Treatment will continue until disease progression, death, intolerability or patient/investigator decision to stop. Primary endpoint is overall survival (OS) in the general study population (HR 0.80 for OS improvement from 8.5 to 10.63 months); secondary endpoints include progression free survival (PFS), OS and PFS in the biomarker positive sub-population, ORR and DCR, safety and quality of life. In addition, blood and tumor archival tissue will be assessed for pharmacokinetic and biomarker analyses. Global enrollment is underway. Clinical trial information: NCT02993731.

Abstract Lung cancer is the deadliest cancer in the United States, contributing approximately 25% of all cancer deaths. Lung cancer risk is well-documented to increase in response to environmental factors, particularly tobacco smoking. As one might expect for a complex trait, there is also a significant genetic risk component in lung cancer, though it is not very well studied. We obtained whole exome sequencing (WES) genotype data from Washington University on 204 subjects from 25 extended families. These individuals were recruited from families with a history of lung cancer and previous analyses showed these 25 families be informative. The purpose of this study is to identify potential risk variants for lung cancer by performing genetic linkage analysis. Quality control was performed on the sequence data, filtering on parameters such as depth (less than 10), genotype quality (less than 10), missingness, and Mendelian inconsistencies. Identity-by-descent (IBD) values were also calculated to verify correct familial relationships. Quality control procedures left approximately 500,000 SNVs and indels for analysis. We performed two-point parametric linkage analysis assuming an autosomal dominant mode of inheritance with a disease allele frequency of 1%, a 10% penetrance for carriers and a 1% penetrance for non-carriers. Two discrete sets of linkage analyses were performed. One was a variant-based analysis, which evaluated linkage between the phenotype and individual SNVs or indels. The second was gene-based analysis, which created a multi-allelic pseudomarker corresponding to a gene from haplotypes of rare variants (minor allele frequency &lt;= 0.01) located within that particular gene. Two-point linkage analysis was then performed on the pseudomarkers. While the variant-based analysis did not identify any genome-wide significant results, several were identified by the gene-based analysis. The highest HLOD scores were both greater than the genome-wide significance level of HLOD = 3.3 and were located on two regions of chromosome 1q: 1q42.13-43 and 1q21.2-21.1. In both regions, the significant HLOD scores clustered around known cancer genes. At the 1q42.13-43 region, signals centered on the cancer-implicated genes OBSCN and RYR2 (also a known mesothelioma gene), while at 1q21.2-21.1 the signals centered on five genes in the neuroblastoma breakpoint family (NBPF) genes, a cluster of recently duplicated genes. NBPF genes have previously been implicated in a variety of different cancers including lung cancer. We are currently performing additional analyses to corroborate the significant results, as well as examining the individual families to determine which families are driving the significant signals. Citation Format: Anthony M. Musolf, Haiming Sun, Bilal A. Moiz, Diptasri Mandal, Mariza de Andrade, Colette Gaba, Ping Yang, Yafang Li, Ming You, Elena Y. Kupert, Marshall W. Anderson, Ann G. Schwartz, Susan M. Pinney, Christopher I. Amos, Joan E. Bailey-Wilson. Whole exome sequencing identifies significantly linked regions on multiple chromosomes in families with a history of lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3276.

How cells ensure symmetric inheritance Parental histones with modifications are recycled to newly replicated DNA strands during genome replication, but do the two sister chromatids inherit modified histones equally? Yu et al. and Petryk et al. found in mouse and yeast, respectively, that modified histones are segregated to both DNA daughter strands in a largely symmetric manner (see the Perspective by Ahmad and Henikoff). However, the mechanisms ensuring this symmetric inheritance in yeast and mouse were different. Yeasts use subunits of DNA polymerase to prevent the lagging-strand bias of parental histones, whereas in mouse cells, the replicative helicase MCM2 counters the leading-strand bias. Science , this issue p. 1386 , p. 1389 ; see also p. 1311

Abstract Hypoxia plays an important role in the genesis and progression of renal fibrosis. The underlying mechanisms, however, have not been sufficiently elucidated. We examined the role of p53 in hypoxia-induced renal fibrosis in cell culture (human and rat renal tubular epithelial cells) and a mouse unilateral ureteral obstruction (UUO) model. Cell cycle of tubular cells was determined by flow cytometry, and the expression of profibrogenic factors was determined by RT-PCR, immunohistochemistry, and western blotting. Chromatin immunoprecipitation and luciferase reporter experiments were performed to explore the effect of HIF-1α on p53 expression. We showed that, in hypoxic tubular cells, p53 upregulation suppressed the expression of CDK1 and cyclins B1 and D1, leading to cell cycle (G2/M) arrest (or delay) and higher expression of TGF-β, CTGF, collagens, and fibronectin. p53 suppression by siRNA or by a specific p53 inhibitor (PIF-α) triggered opposite effects preventing the G2/M arrest and profibrotic changes. In vivo experiments in the UUO model revealed similar antifibrotic results following intraperitoneal administration of PIF-α (2.2 mg/kg). Using gain-of-function, loss-of-function, and luciferase assays, we further identified an HRE3 region on the p53 promoter as the HIF-1α-binding site. The HIF-1α–HRE3 binding resulted in a sharp transcriptional activation of p53. Collectively, we show the presence of a hypoxia-activated, p53-responsive profibrogenic pathway in the kidney. During hypoxia, p53 upregulation induced by HIF-1α suppresses cell cycle progression, leading to the accumulation of G2/M cells, and activates profibrotic TGF-β and CTGF-mediated signaling pathways, causing extracellular matrix production and renal fibrosis.